Styrene has long been used in the manufacture of impact polymers and such polymers have attained a large market for many purposes. Alkylated styrenes such as alpha-methylstyrene have also been of interest for certain purposes. Similarly, nuclear alkyl substituted styrenes have been used in various applications. The monomer which has been principally used is known as vinyltoluene. This is a mixture which consists mainly of meta- and para-methyl styrenes (vinyl toluenes) produced by the catalytic dehydrogenation of a mixture of the corresponding m- and p-ethyltoluenes. The ethyltoluene mixture is itself obtained by the fractional distillation of a mixture of the o-, m- and p-ethyltoluenes. The ratio of the m- and p- isomers in the monomer mixture is approximately 65:35 (m:p). A convenient summary of the preparation and properties of the monomer mixture and of polymers produced from it is given in "Styrene: Its Polymers, Copolymers and Derivatives" Ed. R. H. Boundy, R. F. Boyer, ACS Monograph Series, 1952, Hafner Publishing Company, pages 1232 to 1245.